CVE-2026-82672

Description

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize a strict intermediary and the Mint client on a pooled connection, enabling response-queue poisoning against subsequent requests that share the connection. Mint.HTTP1.Parse.chunk_size/1 in lib/mint/http1/parse.ex stops at the first non-hexadecimal byte of a chunked response's chunk-size line and returns the remainder unexamined. Mint.HTTP1.decode_body/5 in lib/mint/http1.ex then discards every byte up to the CRLF with Parse.ignore_until_crlf/1, so the accepted grammar is a run of hex digits followed by arbitrary bytes, where RFC 9112 permits only a ;-introduced chunk extension. Lines such as 5ZZZZZ and 5 9 are accepted as chunk size 5, and 0ZZZZ is accepted as the terminating chunk that ends the message body. An RFC-strict intermediary rejects such a line while Mint accepts it, so the two disagree on chunk boundaries and on where the response ends. This issue affects mint: from 0.1.0 before 1.10.1.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://cna.erlef.org/cves/CVE-2026-82672.html
• https://github.com/elixir-mint/mint/commit/60089586ec7adc9fddb09f69a2f5919ba9ac7f33
• https://github.com/elixir-mint/mint/commit/c82377838dc6e275ef40bafa664fbcdf50270c60
• https://github.com/elixir-mint/mint/security/advisories/GHSA-rj5m-69wp-cxq9
• https://osv.dev/vulnerability/EEF-CVE-2026-82672

CWEs

CWE-444